Bible Dictionaries
Quaternion

Hastings' Dictionary of the New Testament

(τετράδιον, from τετράς, ‘the number four’; Vulg._ quaternio, whence the English word)

St. Peter, arrested by King Herod Agrippa, was handed over to four quaternions of soldiers (Acts 12:4), probably at the fortress Antonia. A quaternion was a guard consisting of four men, two of whom would be chained to the prisoner in the cell, while the other two kept watch outside (cf. Philo, in Flaccum, 13; Polyb. VI. xxxiii. 7). The second two were apparently the ‘first ward’ (φυλακή), which had to be passed before the iron gate was reached (Acts 12:10). Four quaternions were required, as the night was divided in Roman fashion into four watches of three hours each.

James Strahan.

Bibliography Information
Hastings, James. Entry for 'Quaternion'. Hastings' Dictionary of the New Testament. https://www.studylight.org/​dictionaries/​eng/​hdn/​q/quaternion.html. 1906-1918.